The present disclosure generally relates to sealing between cylindrical components having large radial and axial displacements Turbine engine seals are subject to relatively high and cyclic temperature conditions, ranging from atmospheric to 1600° F. The cyclic temperature variation results in expansions and contractions of parts, including radial and axial displacements of seals within their seats. Within the turbine engine environment, the temperature variation issue is compounded by a need to effectively seal between parts subject to high pressure differentials.
Within a combustion section of a commercial jet engine, a further sealing challenge as related to mid-turbine vanes is in sealing between surfaces that may not be symmetrically oriented relative to one another. For example, in sealing between a conical and a cylindrical surface, particularly where large radial and axial displacements occur, one current approach has been to use a piston ring for accommodating large axial deflections. However, such a ring may require a relatively thick section to provide fairly tall and robust rails in at least one of the relatively movable components in order to provide a groove for capturing the ring and to provide an axial seal face about a full circumference in view of very high and dynamically undulating axial loads and displacements encountered. Such a thick full-hoop section may be subjected to extremely high stresses under the large thermal gradients common to the internal environment of a gas turbine engine.